/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.search;

import org.apache.lucene.search.Filter;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.WildcardTermEnum;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.util.OpenBitSet;

import java.io.IOException;

/**
 * 
 * @version $Id: WildcardFilter.java 922957 2010-03-14 20:58:32Z markrmiller $
 */
public class WildcardFilter extends Filter {
	protected final Term term;

	public WildcardFilter(Term wildcardTerm) {
		this.term = wildcardTerm;
	}

	public Term getTerm() {
		return term;
	}

	@Override
	public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
		final OpenBitSet bitSet = new OpenBitSet(reader.maxDoc());
		new WildcardGenerator(term) {
			public void handleDoc(int doc) {
				bitSet.set(doc);
			}
		}.generate(reader);
		return bitSet;
	}

	@Override
	public boolean equals(Object o) {
		return o instanceof WildcardFilter
				&& ((WildcardFilter) o).term.equals(this.term);
	}

	@Override
	public int hashCode() {
		return term.hashCode();
	}

	@Override
	public String toString() {
		StringBuilder sb = new StringBuilder();
		sb.append("WildcardFilter(");
		sb.append(term.toString());
		sb.append(")");
		return sb.toString();
	}
}

abstract class WildcardGenerator implements IdGenerator {
	protected final Term wildcard;

	WildcardGenerator(Term wildcard) {
		this.wildcard = wildcard;
	}

	public void generate(IndexReader reader) throws IOException {
		TermEnum enumerator = new WildcardTermEnum(reader, wildcard);
		TermDocs termDocs = reader.termDocs();
		try {
			do {
				Term term = enumerator.term();
				if (term == null)
					break;
				termDocs.seek(term);
				while (termDocs.next()) {
					handleDoc(termDocs.doc());
				}
			} while (enumerator.next());
		} finally {
			termDocs.close();
			enumerator.close();
		}
	}
}
